Study On Enantioselective Cytotoxicity And Pesticidal Activity Of Bifenthrin

Synthetic pyrethroids(SPs) are used preferably over organochlorines and organophosphates due to their high effectiveness,low toxicity to mammals and ready biodegradability.Previous studies reported that enantioselective toxicity of SPs occurs in aquatic toxicity,little is known about the differences in the toxicity effects of mammalian cells induced by individual stereoisomers of chiral SPs.The two enantiomers of cis-BF were separated by HPLC on the CHIRALCEL OJ-H column,and the concentration of 1R-cis-BF and 1S-cis-BF were quantified on 6890N-GC。The present study was therefore undertaken to evaluate the enantioselectivity in cytotoxicity,genotoxicity caused by bifenthrin(BF) on human amnion epithelial(FL) cell lines and pesticidal activity on target organism.The cell proliferation analysis indicated that the cytotoxicity sequence of bifenthrin was 1S-cis-BF(55%)＞Racemate(60%)＞1R-cis-BF (82%)(p＜0.05) according to the cell viability of FL cells when the concentration of bifenthrin was above 30mg/L.The elevation of ROS production was incubated with BF in FL cells,and FL cells incubated with 1S-cis-BF exhibited a dose-dependent accumulation of intracellular reactive oxygen species(ROS),and the ROS production of FL cells incubated with 1S-cis-BF was 1.47 times more than 1R-cis-BF at the maximum exposure concentration of 20 mg/L(p＜0.01).In the comet assay,significant differences were observed in DNA tail length of FL cells between the group exposed at concentration of 50mg/L and the control group,and the tail length of damaged DNA incubated with 1S-cis-BF was 3.4 times more than 1R-cis-BF(p＜0.01).The cytoskeleton modification was observed by fluorescent microscope after FITC-phalloidins taining.At fhe concentration of 50mg/L,the damage of cytoskeleton in FL cells incubated with 1S-cis-BF for 24h was very obvious,the abnormal and ncomplete F-actin were observed in FL cells.But in the same condition, FL cells incubated with 1R-cis-BF had almost no effect on the damage of cytoskeleton.The results showed that 1S-cis-BF was stronger than 1R-cis-BF in damaging cytoskeleton for FL cells.The cytoflow analysis indicated that after exposed with BF at the concentration of 5mg/L and 50mg/L,the apoptosis rate of FL cells was increased,and the apoptosis rate of FL cells induced by IS-cis-BF was 3 times more than 1R-cis-BF at the concentration of 50mg/L.While the LC₅₀ values of enantiomer to the target pest on Pieris rapae L.show that 1R-cis-BF was 300 times more active than 1S-cis-BF.According to the experiment study in vivo and in vitro,these results indicated that the enantioselective cytotoxicity and pesticidal activity of bifenthrin between non-target organism and target organism was reverse. These implications together suggest that assessment of the environmental safety and new pesticides development with chiral centers should consider enantioselectivity.